software optimisation vs Australian spelling

software optimisation and Australian spelling both are nouns.

Word	Noun	Adjective	Verb	Adverb
software optimisation	Yes	No	No	No
Australian spelling	Yes	No	No	No

software optimisation (noun)	Australian spelling (noun)
the process of modifying a software system to make some aspect of it work more efficiently or use fewer resources.	English orthography used in Australia (characterized by 'analyse', 'centre', 'usable')